1. Field of the Invention
The present invention relates to an automatic analyzer which conducts the qualitative and quantitative analysis of a biological sample such as blood or urine. In particular, the present invention relates to an automatic analyzer of a type where a light source and a spectral detector are disposed so as to oppose to each other via a reaction container thereby to measure a quantity of light transmitted through the reaction container.
2. Description of the Related Art
The automatic analyzer detects the presence/non-presence or measures a density of an objective component(s) within a biological sample such as blood or urine. Since the automatic analyzer is higher in the analyzing speed and the analyzing accuracy (reproducibility) as compared with a case where a medical technologist measures manually, the automatic analyzers have widely spread mainly in large hospitals and medical laboratories.
The automatic analyzer is arranged to measure absorbance in a manner that the optical axis of a transmission light is shifted sequentially to an adjacent reaction container while rotating reaction containers which are continuously disposed in a circumferential manner. In order to measure the absorbance accurately, the timing of the light measurement is required to be synchronized with the rotation of the reaction containers.
As a technique for satisfying such a requirement, JP-A-9-80055 discloses that detection plates (reaction container position detection means) having the same number as that of the reaction containers are provided in a circumferential manner concentrically above the reaction containers thereby to detect the positions of the reaction containers. JP-A-2000-258433 discloses a technique that the light measurement starting position of a reaction container is determined in accordance with an encoder signal from a direct drive motor having an encoder.